1:05 p.m. update

ALGIERS, Algeria  Algeria’s state news agency says 12 hostages have been killed since the start of the operation to free workers kidnapped by Islamic militants at a natural gas plant in the Sahara.

The APS news agency quotes an unidentified security source for the new death toll and says the fatalities include both Algerian and foreign workers at the remote desert facility.

APS also said Friday that 18 of the hostage takers have been killed.

Earlier

The bloody three-day hostage standoff at a Sahara natural gas plant took a turn Friday as Algeria’s state news service reported that nearly 100 of the 132 foreign workers kidnapped by Islamic militants had been freed.

That number of hostages at the remote desert facility was significantly higher than any previous report, and still meant that the fate of more than 30 foreign energy workers was unclear.

The militants, meanwhile, offered to trade two captive American workers for two terror figures jailed in the United States, according to a statement received by a Mauritanian news site that often reports news from North African extremists.

The Friday report from the government news agency APS, citing a security official, did not mention any casualties in the battles between Algerian forces and the militants. But earlier it had said that 18 militants had been killed, along with six hostages.

It was not clear whether the remaining foreigners were still captive or had died during the Algerian military offensive to free them that began Thursday.